Various types of spinal column disorders are known and include scoliosis (abnormal curvature or rotation of vertebrae relative to the plane of the spine), kyphosis (abnormal backward curvature of the spine) and spondylolisthesis (forward displacement of a lumbar vertebra), all of which involve a "misalignment" of the spinal column. Patients who suffer from such conditions usually experience extreme, debilitating pain and physical deformity due to the condition. In severe cases treatments for these conditions have used a technique known as fusion with spinal fixation which results in the surgical/mechanical immobilization of areas of the spine and the eventual fusion of the vertebrae in the regions treated. In less severe cases treatment comprises decompression of the affected nerve and fusion of the vertebrae involved.
Spinal fixation procedures use the implantation of screws into the vertebra in the affected region of the spine. Clamp assemblies are attached to the screws. The clamp blocks are, in turn, clamped onto a rod which spans adjacent vertebra and thus fixes the vertebrae relative to each adjacent vertebrae. However, none of the existing spinal fixation systems can be used to directly push, pull or rotate the vertebrae to correct a misalignment of the spine by using top adjusting rotating spindle assemblies.
It is desirable that a clamp system be provided which facilitates pushing, pulling or rotating the vertebrae of the spinal column to realign misaligned vertebrae all from a top access position.